/*
 * Copyright 2011 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package eu.vranckaert.calendar.widget;

import android.content.Context;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ScrollView;
import eu.vranckaert.calendar.util.UIUtils;

/**
 * A custom ScrollView that can notify a scroll listener when scrolled.
 */
public class ObservableScrollView extends ScrollView {
    private boolean scrolled = false;
    private OnScrollListener mScrollListener;

    public ObservableScrollView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    @Override
    protected void onScrollChanged(int l, int t, int oldl, int oldt) {
        super.onScrollChanged(l, t, oldl, oldt);
        if (mScrollListener != null) {
            scrolled = true;
            mScrollListener.onScrollChanged(this);
        }
    }

    public boolean isScrollPossible() {
        return computeVerticalScrollRange() > getHeight();
    }

    public void setOnScrollListener(OnScrollListener listener) {
        mScrollListener = listener;
    }

    public static interface OnScrollListener {
        public void onScrollChanged(ObservableScrollView view);
    }

    private boolean haveOtherScrollViewsBeenScrolled() {
        ViewGroup parent = (ViewGroup) this.getParent().getParent();

        for (int child = 0; child < parent.getChildCount(); child++) {
            View view = parent.getChildAt(child);
            if (view instanceof ViewGroup) {
                ViewGroup viewGroup = (ViewGroup) view;
                for (int vgChild = 0; vgChild < viewGroup.getChildCount(); vgChild++) {
                    View vgChildView = viewGroup.getChildAt(vgChild);
                    if (vgChildView instanceof ObservableScrollView) {
                        ObservableScrollView scrollView = (ObservableScrollView) vgChildView;
                        if (scrollView.scrolled) {
                            return true;
                        }
                    }
                }
            }

        }

        return false;
    }

    private void scrollAllOtherScrollViewsTo(int scrollY) {
        ViewGroup parent = (ViewGroup) this.getParent().getParent();

        for (int child = 0; child < parent.getChildCount(); child++) {
            View view = parent.getChildAt(child);
            if (view instanceof ViewGroup) {
                ViewGroup viewGroup = (ViewGroup) view;
                for (int vgChild = 0; vgChild < viewGroup.getChildCount(); vgChild++) {
                    View vgChildView = viewGroup.getChildAt(vgChild);
                    if (vgChildView instanceof ObservableScrollView) {
                        ObservableScrollView scrollView = (ObservableScrollView) vgChildView;
                        scrollView.scrollTo(0, scrollY);
                    }
                }
            }

        }
    }

    @Override
    protected void onLayout(boolean changed, int l, int t, int r, int b) {
        super.onLayout(changed, l, t, r, b);

        boolean otherViewsHaveBeenScrolled = haveOtherScrollViewsBeenScrolled();
        if (!otherViewsHaveBeenScrolled) {
            int nowOffset = -1;

            for (int child = 0; child < getChildCount(); child++) {
                if (getChildAt(child) instanceof BlocksLayout) {
                    BlocksLayout blocksLayout = (BlocksLayout) getChildAt(child);
                    for (int blockChild = 0; blockChild < blocksLayout.getChildCount(); blockChild++) {
                        if (blocksLayout.getChildAt(blockChild) instanceof TimeRulerView) {
                            final long now = UIUtils.getCurrentTime();
                            TimeRulerView timeRulerView = ((TimeRulerView) blocksLayout.getChildAt(blockChild));
                            nowOffset = timeRulerView.getTimeVerticalOffset(now);
                            nowOffset = nowOffset - (this.getHeight() / 2);
                            scrollAllOtherScrollViewsTo(nowOffset);
                        }
                    }
                }
            }
        }
        scrolled = otherViewsHaveBeenScrolled;
    }
}
